1. Field of the Invention
The present invention relates to an X-ray imaging apparatus which generates a three-dimensional image of a blood vessel from images before and after the injection of a contrast medium.
2. Description of the Related Art
There is an examination technique called CTHA (CT during hepatic arteriography) for diagnosing a liver tumor. This is a method of performing CT (Computed Tomography) of a hepatic artery while injecting a contrast medium into it. In general, however, this technique can be implemented by only an apparatus (called an IVR-CT) comprising both a CT apparatus and an angiography apparatus. An IVR-CT is very expensive, and hence only some large hospitals can purchase it.
Recently, there has been proposed a method (to be referred to as soft tissue imaging hereinafter) of improving the visibility of a soft tissue by acquiring many projection images using an X-ray imaging apparatus and reconstructing an image from the many projection images.
It is expected that if soft tissue imaging can do the same thing as CTHA, even hospitals which do not own IVR-CTs can perform the same examination as that described above. On the other hand, even if soft tissue imaging can perform the same examination as that by CTHA, conventional 3D-DSA is an indispensable examination for identifying a nutrition blood vessel and an approach route.
CTHA as soft tissue imaging is, however, inferior to CT in density resolution, and hence requires a larger amount of contrast medium. It is therefore feared that an increasing amount of contrast medium will increase the burden on a patient. See Jpn. Pat. Appln. KOKAI Publication No. 2007-130244.